Overview of the project strategy.

Autologous pairs of mesenchymal stem/progenitor cells (MSPC) and endothelial colony-forming progenitor cells (ECFC) were isolated, purified and expanded from the same human umbilical cord as described (http://www.jove.com/author/Andreas_Reinisch) (A). Cells were combined with matrix and injected subcutaneously in four 300 µL implants per animal into the flank of immune compromised NSG mice as specified (B). Plugs were explanted 24 hours after implantation (C) to detect the signaling signature operative during the early phase of therapeutic vasculogenesis using proteomic profiling on customized antibody microarrays comparing either co-transplants of ECFC+MSPC with transplants containing sole ECFC, MSPC or Matrix in vivo (groups I – III), or co-transplants in vivo with a mixture of ECFC+MSPC created in vitro (group IV) (E). Macroscopic view of plugs explanted after 2, 8 and 24 weeks (C and D). Histology and morphometry were performed to visualize vessel formation and stability in plugs in a time course (for up to 24 weeks) (F and G). Small molecule inhibition of selected targets (from the array analysis) was used as a proof-of-principle confirming drugability of significantly regulated proteins within the early vasculogenesis signaling signature.